(1) Field of the Invention
The present invention relates to a press for press patterns on sheets of paper product and, more particularly, to a press that is able to press large sized sheets without increasing the size of the press.
(2) Description of the Prior Arts
A conventional press for pressing patterns on paper sheets generally includes 13 cm of height, 13 cm of width and 11 cm of depth. The plates for clamping the paper sheets is 15 cm of length and 7 cm of width. The thickness of the two plates is about 0.8 cm. In other words, the width of the rollers is about 8 cm and a gap between the upper and lower rollers is about 0.8 cm. Furthermore, the mold is 6.5 cm of width and 4.5 cm of length. The total thickness of the two molding plates, the paper sheets and the clamping device for clamping the molding plates is about 0.2-0.3 cm. The thickness of the etching mold is about 0.1 cm, and the thickness of the pressing plate has to be increased. The paper sheets are fed into the gap between the upper and lower rollers by rotating a handle to operate a gear set which reduces the effort that the user inputs the press to make the upper and lower rollers to be rotated in opposite directions. Generally, the handle is rotated clockwise to drive a spur gear with small size, and the spur gear with small size drives a spur gear with large size counter clockwise. Another spur gear of small size sharing the same axis of the spur gear with large size is rotated and drives the lower roller to rotate clockwise. A spur gear is connected to a remote end of the lower roller and drives another spur gear on the upper roller so that the upper and lower rollers are rotated in opposite directions to feed the paper sheets forward to finish the engraving or printing processes.
There are several shortcomings for the conventional press mechanism. The first one is that the press mechanism needs many gears. The second shortcoming is that the gears occupy most of the space of the press so that the conventional press is difficult to be improved without increasing its size. The third shortcoming is that the lower roller transfers the energy from one end to the other so as to drive the upper roller and this causes tremendous energy loss. The fourth shortcoming is that if the size of the conventional press is to be increased so as to deal with larger sized paper sheets, there are many difficulties to re-arrange the gears. Besides, the handle is located at a side of the press and makes the press unstable.
The present invention intends to provide a press mechanism with compact size and that uses a worm unit cooperated with worm gears so that the press mechanism can be efficiently operated. The press mechanism is allowed to press A4 size paper sheets.